Typical, I might give the city baths a try, it looks really nice.Mate Eldon is the only one that didn't open. Sucks.
If you find any new ones with open showers do let me know
Have you been to any saunas in Newcastle? I've not really been to many so don't really know the etiquette, do you go naked under a towel? I know in Europe it would be mixed and everyone just strips off but I suspect we are a bit more prudish here!